The present invention relates to a device having a plurality of rotary knobs extending partially through respective slots in a plate member so as to be rotated by engaging the peripheral surface of the knobs, and more particularly, to a device in which a large number of such rotary knobs can be arranged quite closely together.
Assemblies in which a large number of electric components such as variable resistors or switches are disposed in a single case are known, and one example is a variable resistor block typically used for setting and tuning voltage of an electronically-tuned television receiver (hereinbelow, termed "tuning block").
A prior art tuning block of this type is constructed as shown in FIGS. 1 to 3. In a single case 1, a large number of variable resistors 2 are arranged together as close as possible with their longitudinal directions being parallel to one another. The variable resistors 2 are arranged equidistant from one side 1a of the case 1 and each include a respective operating shaft 2a having threads so as to move a slide element longitudinally of the resistor upon rotation. The operating shafts 2a are each fitted within a respective hub portion 3a of a rotary knob 3. The periphery of the rotary knobs 3 protrudes through respective slots 1d in the upper surface 1b of the case 1. The protruded rotary knobs 3 may be turned to operate the respective resistors by engagement with a person's finger so as to drive the variable resistor 2.
In FIGS. 1 to 3, numeral 4 indicates an insulating substrate which is mounted on the bottom of the case 1. Symbol 1c designates slots provided in the upper surface 1b of the case 1 and each having a pointer 2b interlocked with the slide members of the respective variable resistors 2. Terminals 2c of the variable resistor 2 extend through the substrate 4.
In the above construction, the rotary knobs 3 are arranged alternately in two rows with the center of each knob being aligned with the space between knobs of the other row. Such staggered relationship of the knobs 3 allows the variable resistors to be packed densely together and the whole tuning block can thus be made quite compact. Since, however, the rotary knobs 3 are arranged close together, the following drawback is prone to occur. When a desired one of the rotary knobs is being turned, the actuating finger may touch an obliquely adjoining rotary knob and turn it also, so that the preset tuning voltage of an adjoining channel is shifted.